Dehydration or cooling of air or other gases



Nov. 29, 1932. R. w. THOMAS DEHYDRATION OR COOLING' OF AIR OR OTHER GASES Filed Aug. 29, 1929 Patented Nov. 29, 1932 UNITED STATES PATENT OFT-ICE ROSSWELL W. THOMAS, OF .'BARTLESVILLE, OKLAHOMA, ASSIGNOR TO PHILLIPS PETROLEUM COMPANY, OF BARTLESVILLE, OKLAHOMA, A CORPORATION OF DELA- WARE DEHYDRATION OR COOLING OF AIR 0R. OTHER GASES Application led August 29, 1929. Serial No. 389,220.

This invention relates to improvements in the dehydration or cooling of air, low calorific value gas or a finished gas.

In my application SeriaLNo. 362,436, filed May 1l, 1929, I have disclosed a system in which the louT temperature created due to heat absorption by the expansion of light paraffin hydrocarbons or similar gases, is utilized to dehydrate 'air or the like, which is subsequently mixed with the hydrocarbons to produce a combustible gaseous mixture. In that system, the hydrocarbons and air flow adjacent to one another and out of contact in a heat exchanger.

The primary object of the present invention is to improve such system and this I accomplish mainly by bringing the hydrocarbons and the air or other gas into direct contact while the hydrocarbons are expanded, so that the heat absorbed causes refrigeration and precipitation of the aqueous moisture contained in the air or the like.

Another object of this invention is to provide a system in which the air or other gas and the hydrocarbon fluid are pumped in such manner that the volume of the air or other gas is utilized to vary the speed or stroke of the hydrocarbon pump. whereby an increased or decreased amount of hydrocarbon fluid is forced through tbe system as the volume of the air or other gas increases or decreases.

A further object is to provide an apparatus for this purpose in which the hydrocarbon pump is arranged at a lower level than the hydrocarbon supply tank so that the h vdrocarbon pump is always under the influence of the static head produced by the liquefied hydrocarbon fluid.

Another object is to furnish a gas making system or the like in which the ice formed due to the expansion of the hydrocarbon fluid may be readily removed from the system without interfering with the continuous operation of the latter.

With the foregoing objects outlined and with other objects in view which will appear as the description proceeds, the invention novel method of carbureting air or low calov rific value gas with a volatile paralin hydrocarbon fluid, such as butane, propane, ethane or mixtures of the same, or similar hydrocarbons, and at the same time utilizing the latent heat of' vaporization of the liquefied hydrocarbon fluid to refrigerate and dehydrate the air or low calorific value gas. The difference between my present proposal and the disclosure in the above-mentioned patent application is that in the present case the vaporizing hydrocarbon fluid is in direct contact With the stream of air or low B. T. U. gas, and not separated therefrom in a heat exchanger or other device.

I propose that air or any other suitable base gas be supplied at any pressure from atmospheric up to say 100 pounds gauge, by any suitable means, such as a rotary or reciprocating compressor or blower 1, and that the air or gas stream discharged from the pressure pump be measured through a rotary or posi- .tive displacement meter 2, or even through an orifice or Venturi type meter, with the meter so arranged (for instance by means of a conduit 3) in communication with a hydrocarbon pump 4, that the strokes or the movement of the liquid pump Will be proportional' to the air or gas flow. Obviously, a correction for absolute pressure of the air or gas stream must be incorporated, however, in a great many systems the apparatus can Work at a constant pressure, thus eliminating this variable.

The hydrocarbon pump 4 ma be of any suitable design and will prefera l; be positioned ad'acent to and just below t e storage tank 5 w ich contains the liquefied araiiin hydrocarbon gases. The pump wi thus have a positive suction head in addition .to the vapor pressure of the hydrocarbon fluid, or in lother words, the pump will be submerged below the norma liquid level, thus assuring complete filling of its cylinders or clearance spaces and consequent accuratametered delivery of the liquid carburent.

A back pressure valve 6 is preferably installed in the hydrocarbon pum discharge line 7 so that the pump will wor against a discharge pressure higher than the vapor pressure of the hydrocar on fluid under normal operating conditions This will .prevent vaporzation in the pump 4 and its discharge chamber, which 'vaporzation or partial vaporization would perhaps otherwise interfere with the accuracy of proportioning between the pump carburent and the base gas or air.

The latent heat of vaporzation of the liquefied carbureting medium will in one or the other of the chambers 9 and 10, be supplied b the stream of base gas or air flowing throug the discharge line 8, resulting in refrigeration of the mixture to such a low degree that practically complete dehydration will be accomplished. Calculations are available on the extent of such refrigeration for any gliven set of conditions, but it 1s enough to say t at the degree of refrigeration even on very low calorific value finished mixtures, will be sufficiently low to accomplish the dehydrating effect desired.

The temperature level will in fact be, in practically all cases, below the freezing point of water with the possible exception of carburation of a base gas over pressures from 50 pounds gauge upwards; the exact pressure eing depen ent, of course, upon the relative percentages of base gas and carbureting me,- dium, and also on the particular carbureting medium used.

In order to allow for the accumulation of ice and its subsequent removal, I preferably mix the carburent and base gas or bring these fiuids into contact, in either one or the other of the two expansion chambers 9 or 10, wherein the liquid from the pipe 7 will be injected through the end 11 of the pipe into the flowing base gas stream entering through the end 12 of the pipe 8; only one chamber being used at a time and suitable valves 13 being interposed in the pipe lines to properly control the fiow of the fluids..

With such an apparatus, a cycle of operation can be established in which, for instance, one chamber will be used for one week and the second chamber for the subsequent week', durin which latter period the first chamber woul' be allowed to thaw out and the water.`

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leads the resulting dehydrated gaseous mixture to a suitable place of storage or disposal.

By properly proportioning the size of the expansion or refrigerating chambers 9 and 10 and by controlling the cycle of operation, no difficulty will be experienced from the removal or non-removal of the frozen moisture content. The alternation from one carbureting chamber to the other can be accomplished manually b means of the valves, or automatically but 1n most cases manual operation will be desirable inasmuch as the changes will be ver infrequent.

I do not wish to e limited to the use of a plurality of expansion or refrigerating chambers 9, 10, as I am aware that similar results may be accomplished by the use of a single chamber onl Neither do I wisli to limit this ap lication to the dehydrating of air or other ase gas used in making a combustible mixture, as it is obvious that the same inventive idea may be used in the cooling or refrigeration of a base gas or a finished as in various types of gas manufacturing p ants and in gas compressing and cooling operations. In one installation for peak load purposes in which substantially pure butane is employed, such hydrocarbon is injected b hand-controlled means into the discharge ines from a twostage carbureted water gas compressor. In that case, the after-cooler capacity was insufficient and utilization of the latent heat of vaporzation of the liquid butane carburent was very effective in affording additional cooling, thus eliminating the necessity of additional capital investment in after-coolers and, incidentally, this liquid injection resulted in an increased capacity of the discharge ipe line from the plant to the points of distrlbution in the city, due to a reduction in the temperature of all of the gas being pumped through the pipe lines. This, in turn, reduced the power cost at the compressor station. A

From the above it will be noted that the gist of my invention resides in the contacting of a liquefied hydrocarbon gas with any other sultable gas for the pur ose of utilizing the latent heat of vaporization of the hydrocarbon fiuid to refrigerate and/or dehydrate the gas with which it is contacted.

The terms and expressions employed herein are used as terms of description and not of limitation, and there is no intention in the use of said terms and expressions to exclude any of the features shown and described or What I claim and desire to secure by Letters Patent is:

l. In a gas manufacturing method, pumpg a stream of gas, also pumping a stream of a normally gaseous hydrocarbon I'iuid in liquid state, utilizing the iiow of one of said streams to vary the pumping of the other stream, directly contacting the streams in such manner that the hydrocarbon iiuidv in vaporizing will dehydrate and refrigerate the gas stream, separating the moisture from the combined streams, and discharging the combined streams through a common passageway.

2. In a gas manufacturing method, Stoiing a normally gaseous hydrocarbon iiuid in liquid condition in a storage chamber, pumping such fluid from the. bottom portion of the storage chamber and thus interposing the static head of the iuid on the pump, subsequently allowing the hydrocarbon iuid to vaporize, and mixing the same during said vaporization with a refrigerate the latter.

a gas manufacturing method, storing a normally gaseous hydrocarbon fluid in liquid condition, pumping such iiuid from storage past by back pressure barrier, subsequently vaporizing the fluid and mixing a gas with the fluidduring such vaporization to dehydrate and refrigerate said gas.

4. An apparatus of the character described, including a closed storage tank for storing a normally gaseous hydrocarbon iiuid in liquid condition,'a liquid pump communicating with said storage tank and arranged below the same, a pipe line leading from the pump, a nozzle at the end of said pipe line, a vaporizing chamber, the nozzle discharging into the vaporizing chamber, a conduit leading into said vaporizing chamber, means for forcing a gas into said conduit, means for discharging a gaseous mixture from the vaporizing chamber, and means for discharging water from the vaporizing chamber.

5. A method of manufacturing a gaseous gaseous hydrocarbon fluid alternately in separate chambers while the uid is undergoing vaporization from a substantially liquid state to a gaseous state, causing said stream of gas to furnish the latent heat of vaporization for the stream of fiuid while the latter is vaporizing causes freezing of the moisture from the stream of gas, and removing the moisture from each chamber while mixing and Vaporization is takin lace in the other chamber.

RO JWELL W. THOMAS.

gas to dehydrate and A fuel composition, comprising directly mixing a owing stream of a moist base gas with a flowing stream of a normally gaseous hydrocarbon Huid while the latter is vaporizing/ from a substantially liquid state into a gaseous state. and thereby causing the base gas to furnish the latent heat of vaporization for said fluid and the Huid in vaporizing to condense the moisture from the base gas, and discharging the mixture of dehydrated base gas and Huid from the zone of condensation, and separately discharging the condensate from said zone.

6. A method of the character described, comprising mixing a stream of moist oxygen containing gas with a stream of normally IOL 

